Male Hypogonadism and Lower Urinary Tract Symptoms: Testicular Volume as an Independent Predictor

The maximum urinary flow rate (Qmax) is the most clinically relevant uroflowmetry parameter and is strongly associated with the International Prostate Symptom Score. However, traditional predictors such as age, prostate volume, and voided volume (VV) only partially explain the wide variability in Qmax among men with lower urinary tract symptoms (LUTS). Given the recognized role of male hypogonadism in LUTS progression and the potential of testicular volume as a surrogate marker of long-term androgenic status, this study investigated whether testicular volume could serve as a novel predictor of Qmax.

We retrospectively analyzed 170 men with LUTS evaluated between April 2012 and March 2017. All patients underwent uroflowmetry, transrectal ultrasonography, and testicular volume assessment using a Prader orchidometer. Serum prostate-specific antigen and testosterone levels were measured. Pearson correlation analysis was used to explore associations between clinical variables and Qmax, followed by multivariate linear regression to identify independent predictors.

The mean age was 69.3 years, mean total prostate volume (TPV) 66.1 mL, and mean total testicular volume (TTV) 32.2 mL. In univariate analysis, age, height, TPV, TTV, VV, and residual urine (RU) were significantly correlated with Qmax. Multivariate regression demonstrated that TTV (β=0.268, P=0.001), VV (β=0.370, P<0.001), and RU (β=-0.193, P=0.009) were independent predictors, whereas prostate volume, age, and serum testosterone were not.

The TTV is a novel independent predictor of Qmax in men with LUTS. Smaller testicular volume was associated with a lower rate of urinary flow, potentially reflecting the cumulative endocrine decline associated with male hypogonadism. As a simple and noninvasive measurement, TTV can serve as a valuable clinical marker to complement existing assessments, helping to identify patients at higher risk for poor voiding function and guiding further comprehensive evaluations.